ASMI Parallel Intel® FPGA IP Core User Guide

ID 683205
Date 7/02/2019
Public
Document Table of Contents

1.4.5.2. EPCQ/EPCQ-L/EPCQ-A Devices Read Dummy Clock Instruction

By default, the ASMI Parallel Intel® FPGA IP core disables the Read device dummy clock option and uses the default dummy clock value in the Quad-Serial Configuration (EPCQ) Devices Datasheet, EPCQ-L Serial Configuration Devices Datasheet, or EPCQ-A Serial Configuration Device Datasheet.

Although you can configure the dummy clock value in the EPCQ/EPCQ-L/EPCQ-A device, the dummy clock value must be in accordance to the value in the Quad-Serial Configuration (EPCQ) Devices Datasheet, EPCQ-L Serial Configuration Devices Datasheet, or EPCQ-A Serial Configuration Device Datasheet. If you configure the dummy clock value in the EPCQ/EPCQ-L/EPCQ-A device other than default value, the fast read operation fails.

To perform the fast read operation without changing the dummy clock value in the EPCQ/EPCQ-L/EPCQ-A device, enable the Read device dummy clock option. The ASMI Parallel Intel® FPGA IP core configures the dummy clock value to match with the EPCQ/EPCQ-L/EPCQ-A device. When enabling the Read device dummy clock option, the ASMI Parallel Intel® FPGA IP core reads the nonvolatile configuration register of the EPCQ/EPCQ-L/EPCQ-A device for the dummy clock value at the beginning of clock cycles. This dummy clock value is held until the read_dummyclk signal is asserted or until the device resets.

To read the dummy clock value from the volatile configuration register of the EPCQ/EPCQ-L/EPCQ-A device, assert at least one clock cycle of the read_dummyclk signal. The ASMI Parallel Intel® FPGA IP core asserts the busy signal after receiving the read_dummyclk signal. The busy signal remains asserted to indicate operation is in progress and deasserted whenever the operation is completed. If the read_dummyclk signal remains asserted while the busy signal is deasserted after the IP core finishes the operation, the IP core re-registers the operation and carries out the operation again. So, the read_dummyclk signal must be deasserted before the busy signal is deasserted. The dummy clock value is held until the next read_dummyclk signal is asserted or until the device resets.

Figure 11. Read Dummy Clock InstructionThis figure does not reflect the true processing time.
Note: When the busy signal is deasserted, allow two clock cycles before sending a new signal. This delay allows the circuit to reset itself before executing the next command.